Thank you IFLScience for this little gem of a fact. Well, less of a fact and more of an evolutionary hypothesis, but I have to say, it does make sense.
In terms of our evolution, we were never built for car travel. For thousands and thousands of years, our thalamus – the hub of how we process sensory information – became tuned to deal with the sensory input from walking and running. In these processes, our body feels in sync with our wider sense of speed, with our vision and other senses providing a sensory match.
But in a car or train, it’s a different story. Physically, we are sitting still, our muscles aren’t moving, and the air around us feels motionless, yet we have other sensory input that tells us there is a lot of movement going on.
“There’s a sensory mismatch there,” Dr Burnett explains. “And in evolutionary terms, the only thing that can cause a sensory mismatch like that is a neurotoxin or poison. So the brain thinks, essentially, it’s been being poisoned. When it’s been poisoned, the first thing it does is get rid of the poison, aka throwing up.”
This little snippit was taken from a much longer interview on NPR about the “Idiot brain”, i.e. the various apparently illogical ways the brain stores information. If that’s the sort of thing that would interest you, you can listen to it and/or read the transcript here. You can also buy Burnett’s new book, for that matter.